1. Field of the Invention
The present invention relates to a toner which is suitably applicable for an electrophotography, a latent electrostatic recording method, a latent electrostatic printing method and the like. The present invention also relates to an efficient method for producing such a toner. Moreover, the present invention is directed to a developer, a toner container, a process cartridge, an image-forming apparatus, and an image-forming method, all of which employ the aforementioned toner.
2. Description of the Related Art
Dry toners have been conventionally applied in electrophotography, latent electrostatic recording methods, latent electrostatic printing methods, and the like. The dry toners in use are generally obtained by kneading a toner binder such as styrene resin, acrylic resin, polyester resin or the like together with other component such as a colorant, and crushing the mixture.
The conventional dry toners, however, cannot sufficiently satisfy the recent demands such as of high quality, formation of high quality image, and low-temperature fixing properties. Specifically, the dry toners which are crushed and classified have limits in miniaturization of the toner, or crushing yields. Therefore, there is a problem such that a toner having small particle size and sharp particle size distribution, and is capable of forming high quality images cannot be efficiently produced.
To overcome such problems, intensive studies and improvements have been made on chemically prepared toners (CP toners). As a chemically prepared toner, there have been proposed: a polymerization toner which is formed using vinyl monomer or the like in accordance with suspension-polymerization method, emulsification-polymerization-aggregation method, seed-polymerization method, dispersion-polymerization method or the like; and an elongation toner which is formed by subjecting polyester prepolymer an elongation reaction (referred to Japanese Patent Application Laid-Open (JP-A) No. 2002-296839). Among the chemical toners proposed, the elongation toner is most recognized because of use of polyester resin which is advantageous for realizing low-temperature fixing.
However, such an elongation toner has the following drawbacks.
In the process of producing the elongation toner, an oil phase, which prepared by dissolving and/or dispersing toner materials such as polyester prepolymer, a releasing agent, a colorant and the like in an organic solvent, is dispersed in water together with a surfactant and resin particles. Therefore, the obtained toner particles have the resin particles on the surface of the toner particles. Moreover, onto the surface of the toner particles or resin particles, the surfactant, ionic impurities, and the like may be attached. These attachments are liable to decrease charging ability, and thus adversely affect on a resistance of the toner to the environmental changes. To prevent the toner from decreasing its charge ability, it is necessary to wash the toner particles and to remove the attachments therefrom.
As a washing method of the toner, there is proposed a method in which, for example, an emulsification-aggregation toner is sequentially washed with alkaline solution, acidic solution, and water (JP-A No. 2001-175028).
When this washing method is applied to the elongation toner, the ionic impurities or surfactant may be merely removed from the toner particles, but the charging ability is not sufficiently maintained.
As described above, the current situations are such that there have not yet provided a toner having excellent charging ability, shelf stability, low-temperature fixing properties and high quality image formation, a method for producing such a toner, and relative technologies utilizing such a toner.
It is therefore an object of the present invention is to provide a toner and an efficient method for producing the toner which has excellent cleaning ability, shelf stability and low-temperature fixing properties, and attains high quality images. It is another object of the present invention is to provide an image-forming method using the toner formed by the method of the present invention.